Sound reproducer



c. R. SHAW. SOUND REPRODUCER.

APPLICATION FILED JULY 8| l9l8.

1 ,407,002, Patented Feb. 21, 1922.

UNITED STATES PATENT OFFICE.

CLIFFORD R. SHAW, F CHICAGO, ILLINOIS.

nSOUND REPRODUCER. A

Momma.

j useful Improvements in Sound Reproducers,

of which the following is a description, reference being had to theaccompanylng drawi which forms a part of my specification.

y invention relates to sound reproducersy wherein a second or auxiliarydiaphragm i is employed, so constructed and mounted obvia-ted.

that the tones or sounds will not only be -more clearly reproduced, butthe more delicate vibrations or tones, as well as the more forceful orviolent vibrations, will all be reproduced in a distinct, clear, mannerand the original tone quality substantially maintained.

A further object of my invention is to provide a construction whereinthe ringing sounds that are frequently encountered 1nO phonographiereproductions will be eliminated and the hollow tone quality, ofreproducers as heretofore constructed, entirely A further object of theinvention is to provide a construction` employing a second or auxiliarydiaphragm .provided with a plurality of openings for the passage ofthesound 'waves' set up by the flexible 'diaphragm `with which thestylus-bar is conp nected; the openings in the second or auxiliary diahragm being so formed and arranged t at adistinct reproduction vorclearer enunciation isobtainable than has heretofore been the case;theformation of the openings in the second or auxiliary diaphragmtendingto increase the volume and also reproducingthe extremely low mellowtones which have not -been obtained with phonograph reproducers asheretofore constructed. l

My invention also provides a construction whereby the extraneous,mechanical Y sounds, namely the so-called surface possess in theoriginal recorded selection.

The advantages of my improved construction and the" functions of therespectiveelements will be more -readily comprehended Specification ofLetters Patent.

Patented Feb. 21, 1922.

Application led July 8, 191B. Serial No. 243,739.

from the following detailed description of the accompanying drawing,Wherein:-

Figure 1'is a front elevation of my improved reproducer shown secured topart of a tone-arm, with portions of the reproducer shelland flexiblediaphragm l shownQ broken away.

Figure 2 is a vertical sectional view, taken on the line 2 2 of Figure 1looking in the direction of the arrows.

Figure 3'is a detail perspective view of the intermediate memberorauxiliary diaphragm.

Figure 4 is a front view, in perspective, of the reproducer back.

Figure 5 is a perspective view of one-half of a modified form ofintermediate member or auxiliary diaphragm.

In the exempliication of the'k invention, the shell or casin prises theprefera ly circular flanged member'or ring 10 which is removably securedto the ,annular back l1, preferably by means of suitablescrewsadapted'to take through the screw-openings 12 shown in the back,see Figure 4. The back 11 is adapted to be properly secured to the endof the tone-arm,l

a portion whereof is shown at 13 in Figure 1, whereby the tonevibrations or sounds may be conveyed to a suitable tone chamber in aphonograph cabinet or casing not illustrated.

The back 11 is provided with the centrally located outlet 14 and atpoints intermediate of the outlet 14 and the periphery of the back, itfis provided with a plurality of bosses A15, preferably formed integralwith the back and spaced at equi-distances apart.- The bosses 15 arecounterbored or provided with sockets adapted to receive plugs orinserts 16, preferabl of resilient material such as rubber, whlch a'readapted to protrude beyond the outer surface of `the bosses so as tocome into bearing relation with the intermediate member or auxiliarydiaphragm -17 The auxiliary diaphragm or intermediate .member 17 isprovided with a plurality of openings 18, see Figure 3,circumferentlally arranged at a vdistance slightly removed from theouter periphery of the diaphragm and preferably in close relation witheach other, as shown in Figure 3. The perforations 18 are arranged at apoint in the intermediate member or auxiliary diaphragm 17 so as'to bedisposed at a point 1n close ofthe reproducer comproximity to theannular member or ring 10, namely at a point intermediate of the bosses15 of the vback 11 and the flanged member or ring 10, see Figures 1 and2.

The auxiliary member or diaphragm 17 is held in contact with theresilient inserts or plugs 16 by a resilient washer orrubber ring 19which in turn is'maintained in contact with the member 17 by theflexible diaphragm 20 to which the stylus-bar 21 is secured at thecentral point 22. The diaphragm 20 in turn is held in contact withWasher or ring 19, and out of contact with the inwardly disposed flangeof-ring 10; by a' resilient washer or rubber ring 23, which latter isforced or inserted beneath the flange portion of ring 10 and intocontact with the periphery of the flexible diaphragm 20. As is evidentfrom the construction shown and described, the flexible diaphragm 20 isyiebdingly held between the resilient washers or rubber rings 1S) and 23and pei'- mitted free vibratory movement induced by the vibratorymovement of the stylus-bar 21 resulting from the vibratory movementencountered by the stylus or needle 24 in its travel over theindentations formed in the circular grooves of the usual phonographicrecord. I

AThe intermediate or auxiliary diaphragm 17 is preferably formed ofnon-yielding material, preferably sheet metal and for that reason theinner circumference of the flanged member or ring 10 is preferablyprovided with a suitable lining of fabric, indicated at 25, in order toprevent metal to metal contact at the periphery of the auxiliary memberor diaphragm 17 and therefore to eliminate any possibility of chatter orimproper mechanical sounds.l

The apertures or openings 18 in the auxiliary member or diaphragm 17 arepreferably flared or enlarged toward the ,rear side thereof, as shownAin Figure 2, thus permitting a slight gradual expansion of thevibrations or soundwaves, which are set up intermediate of the flexiblediaphragm 20 and the intermediate member or auxiliary diaphragm 17, intheir passage rearward of the auxiliary member and toward the outlet 14in the reproducer back 11.

The flanged member or ring 10 is rovided with the usual pair ofcorrelated -u 26, 26 suitably spaced apart to receive t e cross-barorhead 27 of the stylus-bar. The periphery of the ring 1() at pointsintermediate of the lugs 26 is also provided with a. pair of smalltapered points 28, 28 adapted to bear against the rear side of thecrossliead 27 t0 provide pivotal bearing therefor, see Figure 1; and thecross-head is maintained in pivotal relation with the oints 28 by flatsprings 29, 29 which are sliown removably secured to the lugs 26 bymeans of suitably set-screws 30. The free ends of the flat springs 29are slightly bowed toward, the crosshead`27 and each provided with aslightl spherical burr or point at 31, adapted to ar on the cross-head27; the semispherical points or burrs 31 of the spring members29 beingpreferably adapted to bear on the cross-head at points in alignment withthe point of contact of the crossliead with the pointed pins or lugs 28,28 located on the opposite side of the crosshead; thereby allowing freevibratory movementvof the stylus-bar.

ln Figure 5 I show a slight modification of' the intermediate lmember orauxiliary diaphragm 17, in that the perforations thereof are beveledtoward the center of the auxiliary member or diaphragm on the rear sidethereof, as shown at 32. The openings are circumferentially disposedlike the openings. 18 in Figure 3, with the apertures, however, beingbeveled oi flare'd toward the center of the diaphragm, so that the soundwaves may not only have slight expansion,

but will also be directed in their travel toward the central outlet 14in the reproducer back.

As is evident from the construction shown and described, the bosses 15,with their resilient inserts, maintain the auxiliary member or diaphragm17 in proper spaced relation with the back of the reproducer and theintermediate member or auxiliary diat phragm in turn places the washersor rubber rings 19 and .23 under slight compression with the result thatpropier spaced relation between the flexible iaphragm 20 and theauxiliary diaphragm 17 is maintained; and my improved construction alsotends to deaden any ringing sounds which might be produce by the soundwaves striking against thesecond or auxiliary' dia,- phragm.

It has also been found in. practice that with the bosses, ,whereby theintermediate orauxiliary diaphragm is supported and to that extentreduces the area orI space rearward of the intermediate or auxiliarydiaphragm, the slight hollowness of tone is thereby eliminated'.Furthermore, placin the apertures or openings in the intermediate memberor auxiliar diaphragm 17 in proximity to the outer e ge of thediaphragm, each sound wave produced by the flexible diaphragm will beuninterruptedly transmitted through these apertures or openings, withthe result that a clearer enunciation and reproduction of the selectionis obtained, than is the case where the vibrations or sound waves aretransmitted directl to a single opening in the reproducer bacFurthermore, by flaring or beveling the apertures or openings in theintermediate member or auxiliary diaphragm, the volume is considerablyincreased and extremely low mellow tones, which are usually lost withthe type of reproducers wherein the sound.v Waves are transmitted fromthe iexiblev diaphragm directly through the single central opening oroutlet in the reproducer back, are clearly reproduced, and at the sametime the lsurface noises resulting from the stylus traveling in therecord grooves of the record are greatly reduced.

I have shown and described what I b'elieve to be the best embodiment ofmy in-v vention, but modifications may be made in certain detailswithout, however, departing from the spirit of my invention.

' What I claim is 1. A sound reproducer, comprising ashell or casing,the back whereof is provided with' a central outlet and with a pluralityof bosses arranged in spaced relation intermediate of said centraloutlet and the side wall of the shell or casing, an auxiliary diaphragmdisposed on said bosses and provided witha plurality of aperturesarranged circumferentially in proximit to the periphery of saiddiaphragm, a exible diaphragm disposed in said shell forward of theauxiliary diaphragm, and resilient means disposed intermediate of theauxiliary diaphragm and the flexible diaphragm and intermediate of thelatter and the front portion of the shell or` casing whereby 'bothdiaphragms are maintained in spaced relation with each other.

2. In a sound reproducer, the combination of a shell or casing having acentral outlet in the rear wall thereof, the inner side of said rearwall beinglprovided with a plurality of socketed bosses disposedintermediate of said outlet and the periphery of the rear wallandarranged in spaced relation, equi-distances apart, resilient insertsor plugs mounted in -the sockets of said bosses, an auxiliar plurality oapertures arrangedO circumferentially in proximity to the peripheryv ofsaid diaphragm, lsaid diaphragm being adapted to rest on said resilientinserts or plugs, with a iexible diaphragm arranged diaphragm providedwith a forward of said auxiliary diaphragm and in v spaced relationtherewith, and resilient means disposed adjacent the peripheries of thetwo diaphragms whereby the latter are maintained in spaced relation.

CLIFFORD R. SHAW.

